Explicação passo-a-passo:
1)
12/sen120° = x/sen45°
12/0,866 = x/0,7071
0,866x = 12 . 0,7071
0,866x = 8,4852
x = 8,4852/0,866
x = 9,79
2)
50/sen30° = d/sen135°
50/0,5 = d/0,7071
0,5d = 50 . 0,7071
0,5d = 35,355
d = 35,355/0,5
d = 70,71
